Former Chinese security chief Zhou Yongkang, once a member of the ruling Communist Party's Politburo Standing Committee, has been jailed for life.Zhou, 72, is the highest-ranking Chinese official to fall in President Xi Jinping's anti-graft campaign.All of his assets will also be confiscated.The former security chief wielded vast power as head of the police and courts until his retirement in 2012.Al Jazeera's Adrian Brown, reporting from outside Zhou's vast but now empty family compound in Xi Qiantou, Eastern China, described Zhou as "once arguably one of the most powerful men in China"."Until three years ago, he was master of China's secrets, head of the country's security apparatus," he said."Even a year ago, it would have been impossible for a foreign journalist to stand outside the home of a man who was once one of the most feared and powerful politicians in the land.